Multiple pane

ABSTRACT

The disclosure relates to a multiple pane which includes a pair of glass panels spaced by the spacers and sealed at peripheries thereof. The objective is to provide a multiple pane in which the spacers are formed easily, and a method of preparing the multiple pane. The multiple pane includes: a pair of glass panels; a plurality of spacers interposed between the pair of glass panels; and a hermetic bond to hermetically bond peripheries of the pair of glass panels to each other. The multiple pane contains a space formed between the pair of glass panels, the space being to be sealed so as to be in a reduced pressure state. Each of the plurality of spacers being a porous member formed on one glass panel of the pair of glass panels.

This application is a U.S. continuation application of PCT International Patent Application Number PCT/JP2013/001468, filed on Mar. 7, 2013, claiming the benefits of priority of Japanese Patent Application Number 2012-050052, filed on Mar. 7, 2012 and priority of Japanese Patent Application Number 2012-116196, filed on May 22, 2012, the entire contents of which are hereby incorporated by reference.

The present disclosure relates to multiple panes each including a pair of glass panels stacked and a low-pressure space between the pair of the glass panels.

There has been commercialized a multiple pane. In the multiple pane, a pair of glass panels are arranged facing each other, and a plurality of spacers are interposed between the pair of glass panels, and the pair of glass panels are bonded with a hermetic bond at peripheries thereof, and thus an inside space is defined by the pair of glass panels and the hermetic bond. The air in the inside space is exhausted to reduce the pressure of the inside space.

Such a multiple pane in which the pressure of the inside space is reduced has an air layer with a pressure lower than the atmospheric pressure between the pair of glass panels, and thus it is expected to show a greater heat insulating effect, a greater condensation-prevention effect, a greater sound-dampening effect that are greater than those of a multiple pane in which two glass panels are simply stacked. In recent years, the importance of saving energy has increased, and therefore the multiple pane including the space whose pressure is reduced has attracted a great attention as one type of eco-glass. The depressurized multiple pane is manufactured by: applying a sealant (e.g., low melting glass frit) onto the peripheries of the pair of glass panels separated at a predetermined distance by a plurality of spacers such as metal and ceramics; heating the sealant to hermetically bond the peripheries and thus form a space; and thereafter exhausting air in the inside space via an exhaust pipe made of glass or metal.

For example, Patent document 1 (JP 5-501896 A) and Patent document 2 (JP 11-324059 A) disclose the above-mentioned background arts.

SUMMARY Technical Problem

The present disclosure is aimed to provide a multiple pane in which spacers can be formed easily.

Solution to Problem

The multiple pane according to the present disclosure includes a pair of glass panels, a plurality of spacers interposed between the pair of glass panels, and a hermetic bond to hermetically bond peripheries of the pair of glass panels to each other. The multiple pane contains a space formed between the pair of glass panels, and the space is to be sealed so as to be in a reduced pressure state. Each of the plurality of spacers is the porous member formed on one glass panel of the pair of glass panels.

Advantageous Effects of Invention

In the multiple pane according to the present disclosure, each of a plurality of spacers is a porous member, and therefore the plurality of spacers with desired shapes can be easily formed at desired positions between a pair of glass panels.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are a top view and a cross section illustrating a configuration of the multiple pane of Embodiment 1, respectively;

FIGS. 2A and 2B are a top view and a cross section illustrating a configuration of the multiple pane of Embodiment 2, respectively;

FIGS. 3A and 3B show examples of spectral reflectance characteristics of individual infrared reflective films;

FIGS. 4A and 4B are a top view and a cross section illustrating a configuration of the multiple pane of Embodiment 3, respectively;

FIG. 5 is an enlarged view illustrating a shape of a spacer of the multiple pane of Embodiment 3;

FIG. 6 is an enlarged view illustrating another shape of a spacer of the multiple pane of Embodiment 3;

FIGS. 7A and 7B are a top view and a cross section illustrating a configuration of the multiple pane of Embodiment 4, respectively;

FIG. 8 is an enlarged view illustrating a configuration of a spacer of the multiple pane of Embodiment 4;

FIGS. 9A and 9B are a top view and a cross section illustrating a configuration of the multiple pane including spacers arranged in different patterns, respectively; and

FIGS. 10A and 10B are a top view and a cross section illustrating a configuration of a multiple pane including spacers arranged in other different patterns, respectively.

The figures depict one or more implementations in accordance with the present teaching, by way of example only, not by way of limitations.

DESCRIPTION OF EMBODIMENTS

A multiple pane according to the present disclosure includes: a pair of glass panels; a plurality of spacers interposed between the pair of glass panels; and a hermetic bond to hermetically bond peripheries of the pair of glass panels to each other. The multiple pane contains a space formed between the pair of glass panels, the space being to be sealed so as to be in a reduced pressure state. Each of the plurality of spacers is a porous member formed on one glass panel of the pair of glass panels.

Since the multiple pane according to the present disclosure is configured as described above, it is possible to easily form the plurality of spacers with desired shapes at desired positions between the pair of glass panels. Therefore, it is possible to provide the multiple pane with heat insulation properties and sound insulation properties. Besides, since the spacers are the porous members, the spacers can change their shapes to a predetermined extent, even in a state where the spacers are formed on the glass panel. Therefore, even in a case where there are slight variations between heights of the spacers on the glass panel, the variations are reduced by changes in the shapes of the spacers when the glass panel with the spacers is attached to the opposite glass panel. Hence, the spacers are in good contact with the glass panels in entire faces of the pair of glass panels, and the multiple pane with high strength can be obtained.

In the multiple pane, it is preferable that the plurality of spacers are made from a mixture of a material to compose the plurality of spacers and a binder, and each of the plurality of spacers has pores formed by removing the binder. The material to compose the plurality of spacers is mixed with the binder, and parts of the resultant mixture are arranged at predetermined positions. Subsequently, the binder is removed from each part of the resultant mixture. Consequently, formed can be the plurality of spacers having strength enough to keep an interval between the pair of glass panels to a predetermined value.

Besides, each of the plurality of spacers is porous glass. Since being glass member, the plurality of spacers can be a porous member and formed at desired positions with desired shapes.

Besides, in the multiple pane according to the present disclosure, each of the plurality of spacers is the porous member and may contain hollow silica. With this configuration, it is possible to effectively suppress heat transfer via the spacers. Hence, the multiple pane with excellent heat-barrier characteristics may be realized.

Besides, each of the plurality of spacers is the porous member and may contain a filler made of a heat-resistant ceramic. With this configuration, it is possible to suppress contraction in volume of the spacers.

Furthermore, in this case, the porous member preferably includes crystallized glass. With this configuration, coefficients of thermal expansion of the plurality of spacers can be close to coefficients of thermal expansion of the glass panels.

Besides, each of the plurality of spacers is the porous member and may contain a metal oxide material with electrical conductivity. With this configuration, it is possible to impart infrared reflective characteristics to the spacers, and to realize a multiple pane showing higher heat insulating performance.

Besides, each of the plurality of spacers has porosity ranging from 1% to 20%.

In the multiple pane according to the present disclosure, it is preferable that each of the plurality of spacers is the porous member and includes at least two layers, and the at least two layers includes a layer in contact with one of the pair of glass panels on which the spacers are not formed, and the layer is made of a material having the highest adhesiveness to glass of materials for the at least two layers. With this configuration, the spacers can be in close contact with the glass panel on which the spacers are not formed, and overall strength of the multiple pane can be improved.

Otherwise, it is possible that each of the plurality of spacers is the porous member and includes at least two layers, the at least two layers includes a layer in contact with one of the pair of glass panels on which the spacers are not formed, and the layer has the highest heat-barrier properties of the at least two layers. With this configuration, heat-barrier characteristics of the multiple pane can be improved more efficiently.

In this regard, the plurality of spacers according to the present disclosure are used in a multiple pane. The multiple pane includes a pair of glass panels, the plurality of spacers interposed between the pair of glass panels, and a hermetic bond to hermetically bond peripheries of the pair of glass panels to each other. The multiple pane contains a space formed between the pair of glass panels, and the space is to be sealed so as to be in a reduced pressure state. Each of the plurality of spacers is the porous member formed on one glass panel of the pair of glass panels.

Embodiments will be described below in detail with reference to the drawings appropriately.

Note that the applicants provide the attached drawings and the following description in order to enable any person skilled in the art to sufficiently understand the present disclosure, and do not intend to limit the subject matters of claims. For convenience of explanation, the drawings referred below focus on necessary portions of the multiple pane for describing the present disclosure illustrated in a simplified manner. Therefore, the multiple pane described with reference to the drawings may have any configuration which is not shown in the drawings referred. Furthermore, dimensions of components shown in the drawings do not necessarily reflect dimensions and dimensional ratios of components in practice, exactly.

Furthermore, in the present specification, reducing a pressure of a space to be sealed between the pair of glass panels means allowing the space between the pair of glass panels to be in a state of having a smaller pressure than the atmospheric pressure of the outside. Furthermore, the reduced pressure state in the present specification means a state in which a pressure of the space to be sealed is smaller than the atmospheric pressure of the outside. The reduced pressure state includes a vacuum state in which air inside the space is exhausted to reduce the pressure of the space, and the vacuum state is not limited by degrees of vacuum. In this regard, the reduced pressure state in the present specification includes a state where at least one of various gases such as an inert gas is supplied to the space after exhausting the air inside the space, so long as the pressure of the space containing such a gas is consequently smaller than the atmospheric pressure.

(Embodiment 1)

A multiple pane of Embodiment 1 disclosed in the present application will be described below using FIGS. 1A and 1B.

FIG. 1A is a top view of the multiple pane of the present embodiment, and FIG. 1B is a cross section of the multiple pane of the present embodiment. FIG. 1B shows a cross sectional configuration taken along the line A-A′ of FIG. 1A.

As shown in FIGS. 1A and 1B, the multiple pane includes a pair of glass panels 1 and 2 separated at a distance from each other by a plurality of spacers 3 which are porous members, and a seal 4, which is a hermetic bond, to hermetically bond peripheries of the pair of glass panels 1 and 2 to each other. A space enclosed by the pair of glass panels 1 and 2 and the seal 4 is to be sealed. The air in the space is exhausted via an outlet formed in the glass panel 1 in order to reduce the pressure of the space to a predetermined pressure, and then the outlet is sealed with a metal cap 5, for example. Accordingly, the space becomes a sealed space in the reduced pressure state.

The glass panel 1 and the glass panel 2 are both formed of a sheet of float glass with a thickness of 3 mm, for example. The glass panel 1 has a hole for exhausting, which is used as the outlet and not shown in the drawings.

The spacers 3 are arranged on the glass panel 2 to keep an interval between the glass panel 1 and the glass panel 2 to a predetermined value. The arrangement pitch of the spacers is, 2 cm, for example. Each of the spacers has a circular prismatic shape with a diameter of 0.2 mm and a height of 0.2 mm, and is porous glass made of a glass material. Each spacer used in the multiple pane of the present embodiment is porous glass and has a density which can be adjusted by adding low melting glass microparticles and adding when requested various inorganic microparticles. The spacers are formed on the glass panel 2 by photolithography.

Each of the spacers according to the present disclosure is the porous member having a plurality of pores. More specifically, the spacers of the present disclosure are made from a paste of a glass material applied on the glass panel by the photolithography as described above. In the formation of the spacers, organic components used as a binder, various solvent such as a photosensitizing agent and an ultraviolet absorber, and resin components including other impurities are mostly vaporized in steps of drying and sintering subsequent to applying, and consequently the spacer has the pores that are vacancies of vaporized components. In this regard, the pores of the spacer, which is the porous member according to the present disclosure, include both of an open pore which is exposed on a surface of the spacer and a closed pore which is not exposed on the surface.

Besides, the phrase that “the spacer according to the present disclosure is formed on one glass panel of the pair of glass panels” refers to both of a case where the spacer is formed directly on the glass panel and a case where the spacer is formed on one or two or more thin films on the glass panel, namely, indirectly formed on the glass panel.

When the spacer is made from a photosensitive paste containing a low melting glass material, microparticles of an inorganic material, and a binder by photolithography, the porosity of the spacer which is the porous member ranges from about 1% to 20%, for example. The porosity varies, depending upon components for the spacer, types of resin components such as the binder used for forming the spacer, composition ratios of the photosensitive paste, and manufacturing conditions for the spacer, and the like.

Besides, the spacer according to the present disclosure includes not only the aforementioned spacer having the pores formed by removing the binder but also a spacer which is a porous member having pores derived from a pore[s] that a component to compose the spacer originally has. Such a component originally having a pore[s] may be, for example, hollow silica including a hollow inside itself. In any case, the spacer used for the multiple pane according to the present disclosure is the porous member made of the aforementioned material e.g., glass, and do not include a core member made of glass, metal, or the like inside itself, differently from the spacer included in the multiple pane described in the background art.

The seal 4 is composed of low melting glass frit, for example, and formed by applying the low melting glass frit, with a dispenser for example, onto the periphery of the glass panel 2 on which the spacers 3 have been formed, and then drying the low melting glass frit. The low melting glass frit may be: a bismuth-based seal containing 70% or more Bi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture of organic substances such as ethyl cellulose and terpineol; or a frit paste.

Incidentally, a method of preparing the multiple pane of the present embodiment will be described.

First, the spacers 3 are formed on the glass panel 2 by photolithography. The detailed method for preparing the spacers 3 will be described below. Thereafter, the seal 4 is applied onto the periphery of the glass panel 2 with a dispenser for example, and then is dried. Next, the glass panel 1 and the glass panel 2 are introduced into a furnace with being arranged to face each other, and heated to melt the low melting glass frit to bond the peripheries of the glass panels 1 and 2 with the seal 4. Thereafter, air inside the space in the multiple pane in which the glass panel 1 and the glass panel 2 are bonded is exhausted via an outlet with a rotary pump, for example, and thereafter the outlet is sealed by bonding the metal cap 5 to the outlet.

An example of a formation of the spacers 3 by photolithography will be described below.

First, as a material for forming the spacer 3, a photosensitive paste is prepared. The photosensitive paste is prepared by compounding various components such as inorganic microparticles (e.g., silicon dioxide), an ultraviolet absorber, a photosensitive polymer, a photosensitive monomer, a photopolymerization initiator, and low melting glass microparticles (e.g., bismuth zinc-based particles) so as to have a predetermined composition, and mixing and dispersing them with a triple-roller or a kneading machine.

The photosensitive paste may contain a filler composed of heat resistant ceramic particles such as alumina, zirconia, titan oxide, forsterite, mullite, silicon nitride, aluminum nitride, and silica; or high melting glass particles. Accordingly, it is possible to suppress volume contraction in forming the spacer. The high melting glass available as the filler may have a glass-transition temperature ranging from 570° C. to 1200° C. and a softening temperature ranging from 620° C. to 1200° C., and may have a composition of 15 to 50 wt % silicon oxide, 5 to 20 wt % boron oxide, 15 to 50 wt % aluminum oxide, and 2 to 10 wt % barium oxide, for example.

The viscosity of the photosensitive paste is appropriately adjusted by selecting addition ratios of inorganic microparticles, a thickening agent, an organic solvent, a plasticizer, and or a precipitation inhibitor, and preferably falls within a range of 200 to 200000 cps.

The specific example of the composition of the photosensitive paste may be 43 wt % low melting glass microparticles, 10 wt % zinc oxide fine powder, 26 wt % resin components containing a photosensitive monomer, a photosensitive polymer, a photopolymerization initiator, an ultraviolet absorber, a sensitizer, and an auxiliary sensitizer, and 21 wt % organic solvent serving as the binder.

Thereafter, the photosensitive paste is applied entirely on a surface of the glass panel 2 or partially thereon, namely, on parts of the surface of the glass panel 2 on which the spacers 3 are to be formed. The application method may be screen printing, bar-coating, a roll-coating, or the like. The application thickness is adjusted by selecting the number of times of application, a mesh of the screen, and a viscosity of the paste.

Then, mask exposure is performed with a photo mask being over the photosensitive paste applied onto the glass panel. The shape and dimensions of the spacers in a cross section in a face direction of the glass panel and the positions of the spacers can be appropriately adjusted to desired ones by adjusting a pattern of the mask. The mask used is selected from a negative-type mask and a positive-type mask in accordance with types of the photosensitive organic components. An active light source used in the exposure may emit near-ultraviolet rays, ultraviolet rays, electron beam, or X-rays, for example. Among them, the active light source to emit ultraviolet rays is preferable, and may be a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, or a halogen lamp. Among them, the ultrahigh-pressure mercury lamp is preferable. Although conditions for the exposure vary depending on a desired application thickness, the exposure may be conducted for a time of 10 to 30 min using an ultrahigh-pressure mercury lamp with an output of 5 to 100 mW/cm², for example. After the exposure, development is conducted with a developer by immersing or spraying. The developer may be a commercially available alkaline developer.

Subsequently, sintering is performed in a sintering furnace. The sintering atmosphere and the temperature vary depending on types of the paste and the panel, but the sintering may be performed under air or under nitrogen atmosphere. The sintering may be performed at the sintering temperature ranging 520° C. to 610° C., for example, kept for a time ranging from 10 to 60 min.

In the aforementioned manner, for the multiple pane of the present embodiment, it is possible to form the spacers 3 of the porous glass each of which has a predetermined shape in cross section, a predetermined size, and a predetermined height, on the glass panel 2 at a predetermined pitch. Besides, these spacers 3 have high adhesion to the glass substrate 2.

Furthermore, in the multiple pane of the present embodiment, the spacers are made from the photosensitive material, and therefore can be formed in a smaller size than the known spacers having the core members. Accordingly, when the multiple pane of the present embodiment is used for a window, for example, the spacers are small in size and thus it is difficult for human eyes to detect the spacers. Hence, the window excellent in visibility can be realized.

Note that, when the spacers 3 which are the glass porous member and used in the multiple pane of the present embodiment are made from a paste material containing 53 wt % inorganic and glass microparticles, 26 wt % resin components containing a photosensitive monomer, a photosensitive polymer, and the like, and 21 wt % organic solvent serving as binder, the resultant spacers 3 after sintering contains 99 wt % inorganic and glass microparticles and 1 wt % resin components.

(Embodiment 2)

A multiple pane of the Embodiment 2 according to the present disclosure will be described below using FIGS. 2A and 2B.

FIG. 2A is a top view of the multiple pane of the present embodiment, and FIG. 2B is a cross section of the multiple pane of the present embodiment. FIG. 2B shows a cross sectional configuration taken along the line B-B′ of FIG. 2A.

As shown in FIGS. 2A and 2B, the multiple pane of the present embodiment includes a pair of glass panels 11 and 12 separated at a distance from each other by a plurality of spacers 13 each of which is a porous member, and a seal 14, which is a hermetic bond, to hermetically bond peripheries of the pair of glass panels 11 and 12 to each other. Air in a space enclosed by the pair of glass panels 11 and 12 and the seal 14 is exhausted via an outlet formed in the glass panel 11 in order to reduce a pressure of the space to a predetermined pressure, and then the outlet is sealed with a metal cap 15, for example. Accordingly, the space becomes a sealed space in the reduced pressure state.

The glass panel 11 and the glass panel 12 are both formed of a sheet of float glass with a thickness of 3 mm, for example. The glass panel 11 has a hole for exhausting which is the outlet and not shown in the drawings. An infrared reflective film 16 is formed on a surface, which faces the glass panel 12, of the glass panel 11, that is, an internal surface of the multiple pane. The infrared reflective film 16 has a function of transmitting visible radiation but reflecting infrared radiation.

The infrared reflective film 16 is a thin film of tin oxide (SnO₂), for example. The infrared reflective film 16 has infrared reflective characteristics of reflecting more amounts of infrared radiation in an approximate wavelength range of 800 nm to 2000 nm and far-infrared radiation than an amount of visible radiation in the wavelength range between about 400 nm to about 800 nm.

The spacers 13 are arranged on the glass panel 12 at a pitch of 2 cm, for example. Each of the spacers 13 has a circular prismatic shape with a diameter of 0.3 mm and a height of 0.2 mm, and is composed of porous glass made of a glass material. Each of the spacers 13 of the multiple pane of the present embodiment is made of glass microparticles including hollow silica, for example, and formed on the glass panel 12 by photolithography. In this regard, the hollow silica has a particle diameter of 10 to 300 nm and a shell thickness of about 1 to 15 nm.

The seal 14 is composed of low melting glass frit, for example, and formed by applying the low melting glass frit, with a dispenser for example, onto the periphery of the glass panel 12 on which the spacers have been formed, and then drying the low melting glass frit. The low melting glass frit may be: a bismuth-based seal containing 70% or more Bi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture of organic substances such as ethyl cellulose and terpineol; or a frit paste.

A method of preparing the multiple pane of the present embodiment will be described.

First, on the surface of the glass panel 11 to be opposite the glass panel 12, the infrared reflective film 16 is formed by CVD, for example. In this regard, the glass panel 11 may be low-reflective glass (generally referred to as LowE glass or the like) including the infrared reflective film 16 at its one surface.

Then, the spacers 13 are formed on the glass panel 12 by photolithography. The method for preparing the spacers 13 may be the same as the method described above in Embodiment 1. Thereafter, the seal 14 is applied onto the periphery of the glass panel 12 with a dispenser, for example, and then is dried. Subsequently, the glass panel 11 and the glass panel 12 are introduced into a furnace with being arranged such that the surface of the glass panel 11 on which the infrared reflective membrane 16 has been formed is to be inside the multiple pane, namely, the infrared reflective membrane 16 faces the spacers 13 on the glass panel 12, and heated to melt the low melting glass frit to bond the peripheries of the glass panels 11 and 12 with the seal 14. Thereafter, air in a space inside the multiple pane in which the glass panel 11 and the glass panel 12 are bonded is exhausted via an outlet with a rotary pump, for example, and thereafter the outlet is sealed by bonding the metal cap 15 thereto.

As described above, the multiple pane of the present embodiment includes, at the inside thereof, the infrared reflective film 16 on the surface of the glass panel 11. Therefore, when the multiple pane of the present embodiment is used as a window glass, it is possible to shield heat from sun light with the infrared reflective film 16, and improve a heat insulating effect between an inside and an outside of a room. Besides, in the multiple pane of the present embodiment, the spacers 13 which are the porous members contain hollow silica with the particle diameter of 10 to 300 nm and the shell thickness of about 1 to 15 nm, for example, and therefore the spacers 13 have improved heat insulating properties. Hence, it is possible to effectively prevent heat from transferring between the pair of glass panels 11 and 12 through the spacers 13. Accordingly, it is possible to further improve heat insulating characteristics of the multiple pane.

Note that, in the present embodiment, the case of the infrared reflective film made of tin oxide (SnO₂) is described. However, the infrared reflective film may be made of other oxide such as ITO (Indium tin oxide) and zinc oxide. Besides, the infrared reflective film may be a multilayer film of silver and oxide which are stacked and formed with a sputtering device.

FIGS. 3A and 3B show examples of spectral reflectance characteristics of individual infrared reflective films.

FIG. 3A shows spectral reflectance characteristics of the infrared reflective film which is the tin oxide (SnO₂) film taken as an example in the present embodiment, and FIG. 3B shows spectral reflectance characteristics of the infrared reflective film which is a stack of silver and oxide.

The tin oxide (SnO₂) film whose spectral reflectance characteristics are shown in FIG. 3A is formed by CVD (chemical vapor deposition) on the glass panel and has a thickness of 100 μm. As shown in FIG. 3A, the infrared reflective film of the tin oxide (SnO₂) film has excellent characteristics of having reflectance of 10% for radiation in the visible range of 400 to 800 nm, but having high reflectance of radiation in the infrared range, and in particular, having reflectance of 20% or more for radiation in the far-infrared range in which the wavelength is 1600 nm or more.

The infrared reflective film of the tin oxide (SnO₂) film whose spectral reflectance characteristics are shown in FIG. 3A can be formed by CVD which is performed in a high temperature step for manufacturing the glass panel. Therefore, using such an infrared reflective film has an advantage that the glass panel with the infrared reflective film can be formed at a low cost. Moreover, the infrared reflective film of the tin oxide (SnO₂) film formed in the step at a high temperature has an advantage of being less likely to deteriorate in a subsequent high temperature step and under the environment. Hence, as described below, it is possible to form the spacers on the infrared reflective film. Alternatively, the infrared reflective film can be formed on an outer surface of the multiple pane in view of the fact that the above infrared reflective film is less likely to deteriorate due to changes in humidity and temperature, and oil from user's fingers.

The film having a stack configuration of silver and oxide film whose spectral reflectance characteristics are shown in FIG. 3B is an infrared reflective film with a thickness of 100 nm formed by stacking on the glass panel a zinc oxide film with a thickness of 30 nm, a silver (Ag) film with a thickness of 10 nm, a zinc oxide film with a thickness of 20 nm, a silver (Ag) film with a thickness of 10 nm, and a zinc oxide film with a thickness of 30 nm by CVD. As shown in FIG. 3B, the infrared reflective film with the stack configuration of silver and a zinc oxide film has excellent characteristics of having low reflectance ranging 5% to 10% for radiation in the visible range of about 400 to 700 nm, but having high reflectance of red light radiation and longer wave radiation than red light having wavelengths of 750 nm or more, and in particular, having reflectance of about 80% or more for infrared radiation of a wavelength of about 1000 nm or more.

As shown in FIG. 3B, the infrared reflective film of stacked films of silver and an oxide film has high reflective characteristics with regard to infrared radiation. Therefore, it is possible to improve a shielding effect of heat from sun light of the multiple pane including the infrared reflective film, and obtain a multiple pane showing a high heat insulating effect. In this regard, an infrared reflective film formed by sputtering is prone to be poor in stability to high temperature and the environment, compared with the aforementioned infrared reflective film formed by CVD. Therefore, it is necessary to pay attention on an infrared reflective film in a case where a spacer is formed on the infrared reflective film and/or a case where the infrared reflective film is formed on the outer surface of the multiple pane.

Besides, in the multiple pane of the present embodiment, when a material for composing the porous glass of the spacer 13 contains glass, crystallized glass, and a filler such as titanium oxide and zirconium, it is possible to improve strengths of the spacer 13 to mechanical and thermal shocks. The crystallized glass refers to a material, which is formed by dispersing crystals having negative thermal expansion properties into glass to offset thermal expansion of the glass with the negative thermal expansion of the crystal and consequently has a small coefficient of thermal expansion.

Furthermore, in a case of using a material having a coefficient of thermal expansion equivalent to the coefficient of thermal expansion of the glass panel ranging from 8.5*10⁻⁶ to 9.0*10⁻⁶° C. as the material for the spacer 13, it is possible to reduce strain due to stress caused by a difference in the coefficient of thermal expansion in a high temperature process. Therefore, it is possible to improve strength of the multiple pane.

Besides, by selecting the composition of the material composing the porous glass of the spacer 13 so that the material contains an electrical conductive oxide material such as ITO, zinc oxide, titanium oxide, and tin oxide, it is possible to impart the infrared reflective characteristics to the spacer 13 itself. Then, owing to the spacers made of the material with the infrared reflective characteristics, it is possible to further improve infrared reflective performance of the infrared reflective film on the glass panel, and therefore to provide the multiple pane showing higher heat insulating performance.

Note that, in above-described Embodiment 2, the example is described in which the infrared reflective film 16 is formed on the surface, that serves as the internal surface of the multiple pane, of the glass panel 11 on which the spacers are not to be formed, the glass panel 11 being one of the pair of glass panels constituting the multiple pane. However, the infrared reflective film 16 may be formed on the surface, which serves as another internal surface of the multiple pane, of the glass panel 12 on which the spacers are to be formed. Furthermore, the infrared reflective films may be individually formed on the internal surfaces defined by the glass panel 11 and the glass panel 12. In a case of forming the infrared reflective films on both the pair of glass panels, it is possible to obtain the multiple pane showing higher heat insulating effect, compared with a case of forming the infrared reflective film on either one of the glass panels.

In this regard, the infrared reflective film may be formed at the outside on the glass panel, and in this case, heat insulating effect owing to reflection of infrared radiation can be obtained. However, as described above, the infrared reflective film formed by sputtering, for example, is susceptible to the surrounding, and therefore there is high possibility of occurring problems such as deterioration of the infrared reflective characteristics and change in color of the infrared reflective film. Therefore, when the infrared reflective film is formed at the outside on the glass panel composing the multiple pane, it is effective to adopt a configuration for protecting the infrared reflective film. For example, the method of preparing the infrared reflective film may be modified so that the infrared reflective film is less likely to deteriorate, for example, by changing the material or configuration of the infrared reflective film. Furthermore, the infrared reflective film may be covered with a further glass panel or a resin panel.

Besides, when the infrared reflective film is made of an electrical conductive material, there is possibility of an unfavorable effect due to electromagnetic shielding, for example, occurrence of a problem that mobile phones in a room cannot communicate. Therefore, in the case of forming the infrared reflective film on the multiple pane, it is preferable to design the infrared reflective film in view of the electromagnetic shielding in addition to the intended infrared reflective characteristics of the infrared reflective film. In designing the infrared reflective film, the material used for the infrared reflective film may be selected, and it may be determined whether the infrared reflective film is formed on only one glass panel of the multiple pane or on both of the glass panels.

(Embodiment 3)

A multiple pane of Embodiment 3 according to the present disclosure will be described below using FIGS. 4A to 6.

FIG. 4A is a top view of the multiple pane of the present embodiment, and FIG. 4B is a cross section of the multiple pane of the present embodiment. FIG. 4B shows a cross sectional configuration taken along the line C-C′ of FIG. 4A. FIG. 5 is an enlarged view illustrating a configuration of primary parts where the spacer is provided in FIG. 4B.

As shown in FIGS. 4A and 4B, the multiple pane includes a pair of glass panels 21 and 22 separated at a distance from each other by a plurality of spacers 23 which are porous members, and a seal 24, which is a hermetic bond, to hermetically bond peripheries of the pair of glass panels 21 and 22 to each other. Air in a space enclosed by the pair of glass panels 21 and 22 and the seal 24 is exhausted via an outlet formed in the glass panel 21 in order to reduce a pressure of the space to a predetermined pressure, and then the outlet is sealed with a metal cap 25, for example. Accordingly, the space becomes a sealed space in the reduced pressure state.

The glass panel 21 and the glass panel 22 are both formed of a sheet of float glass with a thickness of 3 mm, for example. The glass panel 21 has a hole for exhausting, which is the outlet and not shown in the drawings.

The spacers 23 are arranged on the glass panel 22 at a pitch of 2 cm, for example. Each of the spacers 23 has a circular prismatic shape with a diameter of 0.4 mm and a height of 0.1 mm, and is made of porous glass. With regard to each of the spacer 23 of the multiple pane of the present embodiment, as shown in FIG. 5, a cross-sectional shape of the spacer 23 is such a U-shape that a center of a surface of the spacer 23 in contact with the facing glass panel 21 is set back.

The seal 24 is composed of low melting glass frit, for example, and formed by applying the low melting glass frit, with a dispenser for example, onto the periphery of the glass panel 22 on which the spacers have been formed, and then drying low melting glass frit. The low melting glass frit may be: a bismuth-based seal containing 70% or more Bi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture of organic substances such as ethyl cellulose and terpineol; or a frit paste.

A method of preparing the multiple pane of the present embodiment will be described.

First, the spacers 23 are formed on the glass panel 22 by photolithography. In the method of preparing the multiple pane of the present embodiment, the active light source and exposure conditions for forming the spacers 23 are adjusted so that the central region of the top face of the spacer is recessed and thus the cross-sectional shape of the spacer is the U-shape as shown in FIG. 5. Note that the spacer 23 whose the cross-sectional shape is the U-shape so that the recess is formed in the top face as shown in FIG. 5 can be formed by adjusting the sintering temperature in forming the spacer 23 to a relatively low temperature in a range of 520° C. to 610° C., for example.

Thereafter, the seal 24 is applied onto the periphery of the glass panel 23 with a dispenser for example, and then is dried. Next, the glass panel 21 and the glass panel 22 are introduced into a furnace with being arranged to face each other, and heated to melt the low melting glass fit to bond the peripheries of the glass panels 21 and 22 with the seal 24. Thereafter, air in a space inside the multiple pane in which the glass panel 21 and the glass panel 22 are bonded is exhausted via an outlet with a rotary pump, for example, and thereafter the outlet is sealed by hermetically bonding the metal cap 25 thereto.

As described above, in the multiple pane of the present embodiment, the face of each spacer 23 in contact with the facing glass panel 21 is formed into an U-shape, and therefore in joining the pair of glass panels 21 and 22 with the seal 24 with the pair being arranged to be in contact with each other, an end of the spacer 23 is changed in shape to be fitted on the face of the glass panel 21 that defines the internal face of the multiple pane. Hence, the spacers 23 formed on the glass panel 22 can compensate for slight variations between the heights of the spacers 23 and deformation of the glass panels 21 and 22.

Besides, as shown in FIG. 6, also in a case where the face of each spacer 23 in contact with the facing glass panel 21, which is the top face of the spacer, is formed into a projecting shape in which the center of the top face projects, the spacers 23 can compensate for slight variations between the heights of the spacers 23 and deformation of the glass panels 21 and 22, similarly to the case where the contact face with the glass panel 21 is formed into the recessed shape. The spacers having the top face with the projecting shape as shown in FIG. 6, can be realized by adjusting the active light source and the exposure conditions in forming the spacers as described above. The spacers 23 having the cross section in which the top face is formed into the projecting shape as shown in FIG. 6 may be formed by adjusting the sintering temperature in forming the spacers 23 to a temperature relatively as high as 610° C. to 630° C., for example.

(Embodiment 4)

A multiple pane of the Embodiment 4 according to the present disclosure will be described below using FIGS. 7A to 8.

FIG. 7A is a top view of the multiple pane of the present embodiment, and FIG. 7B is a cross section of the multiple pane of the present embodiment. FIG. 7B shows a cross sectional configuration taken along the line D-D′ of FIG. 7A. FIG. 8 is an enlarged view illustrating a part where the spacer is provided in FIG. 7B.

The multiple pane as shown in FIGS. 7A and 7B includes a pair of glass panels 31 and 32 separated at a distance from each other by a plurality of spacers 33, and a seal 34, which is a hermetic bond, to hermetically bond peripheries of the pair of glass panels 31 and 32 to each other. Each of the plurality of spacers 33 is a porous glass member and includes two layers which are stacked, and the cross sectional configuration of one of the spacers 33 is shown in FIG. 8. Air inside a space enclosed by the pair of glass panels 31 and 32 and the seal 34 is exhausted via an outlet formed in the glass panel 31 in order to reduce the pressure of the space to a predetermined pressure, and then the outlet is sealed with a metal cap 35, for example. Accordingly, the space is formed into a sealed space in the reduced pressure state.

The glass panel 31 and the glass panel 32 are both formed of a sheet of float glass with a thickness of 3 mm, for example. The glass panel 31 has a hole for exhausting.

The spacers 33 are arranged on the glass panel 32 at a pitch of 2 cm, for example. Each of the spacers 33 has a circular prismatic shape with a diameter of 0.4 mm and a height of 0.2 mm, and is made of porous glass. Each of the spacers 33 has a two layer configuration in which an upper spacer layer 37 and a lower spacer layer 38 are stacked. The lower spacer layer 38 is composed of inorganic microparticles of silicon dioxide or the like and low melting glass microparticles e.g., bismuth zinc-based microparticles, and the upper spacer layer 37 is formed on the lower spacer layer 38. The upper spacer layer 37 is preferably made of a material having a softening temperature lower than the softening temperature of the low melting glass contained in the material for the lower spacer layer 38. For example, when the softening temperature of the low melting glass contained in the material for the lower spacer layer 38 is 510° C., the softening temperature of the material for the upper spacer layer 37 is 480° C.

The seal 34 is made of low melting glass frit, for example, and the low melting glass frit is applied, with a dispenser for example, onto a periphery of the glass panel 32 on which the spacers 33 have been formed, and then dried. Thereafter, the glass panel 32 and the glass panel 31 are introduced into a funeral with being arranged so as to face each other, and then heated to melt the low melting glass frit to join and seal them. At the time, the low melting glass contained in the upper spacer layer 37 is melt and then set. Therefore, close contact is made between the glass panel 31 and the spacers 37.

A method of preparing the multiple pane of the present embodiment will be described below.

First, the lower spacer layers 38 are formed on the glass panel 32 by photolithography. In this regard, the lower spacer layers 38 are subjected to the steps of application and drying of the photosensitive paste and exposure in a manufacturing process using photolithography. Then, a photosensitive paste for the upper spacer layer 37 is applied onto the photosensitive paste for the lower spacer layer 38 yet to be developed, then dried, and subjected to exposure. After the exposure, the photosensitive pastes for the upper spacer layer 37 and for the lower spacer layer 38 are developed at one time, and then sintered. Consequently, the spacers 33 with the two layer configuration are formed.

Thereafter, the seal 34 is applied onto the periphery of the glass panel 32 with a dispenser for example, and then is dried. Next, the glass panel 31 and the glass panel 32 are introduced into a furnace with being arranged to face each other, and heated to melt the low melting glass fit to bond the peripheries of the glass panels 1 and 2 with the seal 34. Thereafter, air in a space inside the multiple pane in which the glass panel 31 and the glass panel 32 are bonded is exhausted via an outlet with a rotary pump, for example, and thereafter the outlet is sealed by bonding the metal cap 35 thereto to form a sealed space whose pressure is reduced.

As described above, since the multiple pane of the present embodiment includes the spacers with the two layer configuration, adhesion between the glass panel 31 and the spacers 33 is improved, and consequently, overall strength of the multiple pane is improved.

Besides, in the multiple pane as described in the present embodiment, when the upper spacer layer 37 contains a heat shielding material such as hollow silica, heat transfer between the pair of glass panels is reduced. Hence, heat insulating properties of the multiple pane can be improved.

According to the applicant's study, in the case of using the spacers having the two layer configuration used in the multiple pane of the present embodiment, when either one of the upper spacer layer and the lower spacer layer contains a heat shielding material, heat insulating effect shown by the multiple pane can be increased. Furthermore, in the case, when the upper spacer layer is selected to have heat shielding properties, the heat shielding effect is more improved, compared with when the lower spacer layer is selected to have heat shielding properties. Specifically, in an example, an upper spacer layer with heat shielding properties composed of low melting glass containing 10 wt % hollow silica was formed on a lower spacer layer with a thickness of 0.07 mm made of low melting glass fine powder and had the thickness of 0.05 mm. Furthermore, in another example, an upper spacer layer with no special heat shielding properties composed of low melting glass alone was formed on a lower spacer layers with a thickness of 0.07 mm made of the same low melting glass fine powder as the former example, and had the thickness of 0.05 mm. Consequently, the spacers of the two examples had the two layered configuration and the total thickness of 0.12 mm. The thermal conductivity of the spacer with heat shielding properties of the former example was about 97% based on the thermal conductivity of the spacer with no special heat shielding properties of the latter example.

Besides, the spacers necessarily do not have the configuration where two layers are stacked, and may have a configuration where three or more layers are stacked. When the spacers have the configuration where three or more layers are stacked, in order to improve strength of the multiple pane by increasing adhesion of the spacers to the facing glass panel, the uppermost layer spacer is preferably made of a material having a low softening temperature. In addition, also in the case where the spacers contain the material with high heat shielding properties such as hollow silica, and have a layered formation, the uppermost layer of the spacer is preferably made of a material with the highest heat shielding properties.

Note that, in the case of forming the layers of the spacer having the two layer configuration both by photolithography, the spacer is necessarily not formed in the aforementioned manner. For example, the photosensitive paste for the upper spacer layer 37 may be applied, after development and sintering of the lower spacer layer 38. Otherwise, the lower spacer layer 38 is formed by photolithography, and then the upper spacer layer 37 may be formed by screen printing or other printing.

(Other Embodiments)

As described above, the multiple panes according to the present disclosure are specifically described using Embodiments 1 to 4 as examples of the multiple pane. However, the multiple panes according to the present disclosure are not limited to these embodiments, and may include embodiments modified by appropriate changes, substitutions, addition, and omission. Besides, the multiple panes according to the present disclosure may include new embodiments obtained by combining components described in Embodiments 1 to 4.

Incidentally, other embodiments than Embodiments 1 to 4 will be described collectively.

In the aforementioned embodiments, described is the step of forming the sealed space in the reduced pressure state by joining the pair of glass panels with the seal and subsequently exhausting the air in the space inside the multiple pane. However, this step may be substituted by a step of joining the pair of glass panels by melting the seal in parallel with exhausting the air in the space inside the multiple pane.

In the aforementioned embodiments, the air in the space inside the multiple pane is exhausted and subsequently the outlet is bonded to the metal cap to be sealed, for example. However, an outlet tube which is a glass tube may be attached to the outlet, the air in the space inside the multiple pane may be exhausted via the outlet tube, and thereafter the outlet tube may be cut by melting the outlet tube to seal the space.

In the aforementioned embodiments, the glass panel composing the multiple pane is formed of float glass, for example. However, the glass panel may be not only made of float glass but also be a glass panel made of soda-lime glass, high-strain glass, chemically toughened glass, physically toughened glass, non-alkali glass, quartz glass, Neoceram, borosilicate glass, or Tempax.

In the aforementioned embodiments, the pair of glass panels have the same outer shape and the same thickness (3 mm, for example), for example. However, it is not intended to prevent that dimensions and/or the thickness of one glass panel are different from those of the other glass panel. Besides, the dimensions of the glass panel may vary depending on the application, and include a length of one side several cm, at smallest, or a length of one side about 2 to 3 m, at maximum for use of a window glass. The thickness of the glass panel may vary depending on the application, and may be about 2 to 3 mm at smallest, or may be about 20 mm at greatest.

In the aforementioned embodiments, the spacer is described as a spacer with such an approximately circular prismatic shape that a horizontal sectional shape of the spacer is circular, for example. However, the shape of the spacer is not limited to the circular prismatic shape described above, but may be selected from various shapes such as a prismatic shape having a horizontal sectional shape in the face direction of the glass panel being rectangular, triangular, or polygonal.

Besides, the dimensions of the spacer are not limited to those described above, and are selected appropriately in accordance with the size and the thickness of the glass panel used, the interval between the glass panels, and the like.

An arrangement pattern, an arrangement pitch, a size distribution on the glass panel of the spacers are appropriately selected.

FIGS. 9A and 9B show the first example of the multiple pane having variations both in the arrangement pitch of the spacers on the glass panel and in the size distribution of the spacers, the size referring the dimensions of the spacer in the face direction of the glass panel. FIG. 9A is a top view of the first example of the multiple pane, and FIG. 9B shows a cross sectional configuration of the first example of the multiple pane. FIG. 9B also shows a cross sectional configuration taken along the line E-E′ of FIG. 9A.

As shown in FIGS. 9A and 9B, in the first example of the multiple pane having variations in the arrangement pitch and the size distribution of the spacers on the glass panel, the spacers between the pair of glass panels 41 and 42 include spacers 43 at a peripheral region and spacers 44 at a central region. The spacers 43 at the peripheral region have a smaller size than that of the spacers 44 at the central region. Besides, the spacers 43 at the peripheral region are arranged at a narrower arrangement pitch than that for the spacers 44 at the central region. Specifically, the arrangement pitch for the spacers 43 at the peripheral region is 1.5 cm and the arrangement pitch for the spacers 44 at the central region is 2.0 cm, for example. Besides, the diameter of the spacers 43 at the peripheral region is 0.3 mm while the diameter of the spacers 44 at the central region is 0.5 mm. Owing to variations in the arrangement pitch and the size of the spacers formed on the glass panel 42 as described above, when an external force is applied on the periphery of the multiple pane, more spacers can receive the external force and distribute it. Hence, it is possible to effectively prevent breakage of the multiple pane and peeling of the seal 45.

FIGS. 10A and 10B show the second example of the multiple pane having variations both in the arrangement pitch of the spacers on the glass panel and in the size distribution of the spacers, the size referring the dimensions of the spacers in the face direction of the glass panel. FIG. 10A is a top view of the second example of the multiple pane, and FIG. 10B shows a cross sectional configuration of the second example of the multiple pane. FIG. 10B also shows a cross sectional configuration taken along the line F-F′ of FIG. 10A.

As shown in FIGS. 10A and 10B, in the second example of the multiple pane having variations in the arrangement pitch and the size distribution of the spacers on the glass panel, the spacers include spacers 53 at a peripheral region and spacers 54 at a central region. The spacers 53 at the peripheral region have a greater size than that of the spacers 54 at the central region. Besides, the spacers 53 at the peripheral region are arranged at a wider arrangement pitch than that for the spacer 54 at the central region. Specifically, the arrangement pitch for the spacers 53 at the peripheral region is 2.0 cm, and the arrangement pitch for the spacers 54 at the central region is 1.5 cm, for example. Besides, the diameter of the spacers 53 at the peripheral region is 0.5 mm, and the diameter of the spacers 54 at the central region is 0.3 mm. Owing to variations in the arrangement pitch and the size of the spacers formed on the glass panel 52 as described above, when the multiple pane is used as a window pane, for example, the spacers near the seal are small and therefore are less likely to be visually perceived. Hence, a multiple pane excellent in appearance can be obtained. Furthermore, an interval between the spacers 53 which are at the central region and far from the seal is smaller, and the spacers 53 have a smaller diameter in a horizontal direction. Therefore, it is possible to realize the multiple pane which includes the spacers less likely to be visually perceived and nevertheless is capable of suppressing a change in the shape of the multiple pane caused by flexure of the glass panels.

Note that in the examples of the multiple pane shown in FIGS. 9A and 9B and the multiple pane shown in FIGS. 10A and 10B, the variations in the arrangement pitch and the size of the spacers depend on a position of the spacer on the glass panel, and a region on the glass panel is classified into two regions of the peripheral region and the central region, and, in each of the peripheral region and the central region, the size and the arrangement pitch for the spacers are constant. However, the multiple pane according to the present disclosure may include three or more regions of which the arrangement pitches and the sizes of the spacers are different from each other. Furthermore, in each of the regions, the arrangement pitch and/or the size of the spacers may vary in a stepwise manner. Besides, instead of dividing the glass panel into such regions, the pitch and/or the size of the spacers may vary in a stepwise manner from one edge to another edge, for example.

Besides, by making use of the fact that the spacers used in the multiple pane of the present disclosure are formed by the photolithography, by adjusting the pattern of the exposure mask, the spacers can be arranged on the glass panel of the multiple pane to show a pattern that is perceived by a user as being meaningful.

The pattern that is represented by the arrangement of the spacers and is perceived as being meaningful may include various words such as the product name of the multiple pane. Furthermore, the various words may include a name and a telephone number of a shop, when the multiple pane is used for a show window of the shop. Similarly, such a pattern may include logos of the multiple pane per se and/or a manufacturer of the multiple pane. Furthermore, when the multiple pane is used as a window pane of a shop or a facility or when the multiple pane is used as a window of an information research system box for a public internet terminal or the like, such a pattern may include figures and/or symbols recognized as a meaningful mark providing various meanings e.g., a mark symbolizing services the facility can provide.

Note that a method of preparing the pattern of the spacers recognized as being meaningful may be a similar method of arranging dots to form predetermined words or figure as a whole, or a method of adjusting the pattern of the exposure mask so as to form the spacers having shapes of desired words or figures as they are. The method of arranging dots to form words or figure as a whole is conducted by adjusting a degree of density, which is the arrangement pitch, of the spacers and/or adjusting a shape or dimensions of the cross section of the spacers in a horizontal direction.

Besides, by applying the technique of varying the arrangement pitch and size of the spacers in an entire region over the glass panel constituting the multiple pane as described above using FIGS. 9A to 10B, it is possible to form gradation of light and shade on an entire surface of the glass panel and/or form a pattern such as a check pattern and a zigzag pattern.

Furthermore, by varying color, reflectivity, and luster of a material for constituting at least part of the spacer depending on a formation region, the meaningful pattern defined by the spacers may be formed as a colored pattern. As such a method of varying the color of the spacers, a method of applying a photosensitive paste with desired colors on individual parts of the glass panel is effective. Besides, when the spacers with the two layer configuration are used like Embodiment 4 described using FIGS. 9A and 9B, the upper spacer layer is formed by printing, for example, it is remarkably facilitated to form spacers with a desired color in a desired region.

In each of the multiple panes of embodiments according to the present disclosure, the glass panel is in a flat plate shape. However, the multiple pane according to the present disclosure includes a multiple pane using curved glass panels having strength which is not less than a predetermined value even in a state where the inside of the multiple pane has a reduced pressure. Examples of the curved glass panel include: a glass panel which is curved in one direction; a glass panel which is curved in all directions like a shape of parts of a sphere; and a glass panel with a wave-like shape having some units with asperity. Besides, the pair of glass panels need not have the completely same curvature degree. In the multiple pane, a distance between two glass panels may vary according to positions, within a range in which the spacers with a desired height can be formed.

These multiple panes using the curved glass panels are curved as a whole, and therefore exhibit high designability when used in a window and has high usefulness because they are available in cases where it is not possible to use a planar multiple pane in view of constraints on shapes for members to be fitted.

Besides, by forming a predetermined printed pattern on parts whose appearance is not good such as the seal to seal the multiple pane and the outlet, the multiple pane may have high designability.

Note that the infrared reflective film as formed in the multiple pane of Embodiment 2 described using FIGS. 2A and 2B may be included in the configurations of the multiple panes of Embodiment 3, Embodiment 4, and the other embodiment having various variations. By being configured to include the infrared reflective film, the multiple panes can show improved heat insulating effect in addition to the individual features of configurations of the individual embodiment.

Besides, in the multiple pane according to the present disclosure, when the seal is made of a sealant which melts at a relatively low temperature e.g., 300° C., the material to compose the spacers may be a resin material. For example, the porous material may be formed of by adding an inorganic material such as silicon dioxide, titanium dioxide, crystallized or amorphous glass fine powder, and hollow silica, into the resin material instead of a low melting glass material.

Besides, already established techniques related to the multiple pane may be appropriately added to and applied in the multiple pane according to the present disclosure. The already established technique includes a formation of an organic or inorganic film in order to impart, to the glass panel, various optical properties of antireflection and/or absorbing ultraviolet rays, or functions of heat insulating characteristics and the like.

Furthermore, by using the multiple pane per se as at least one glass panel of the pair of glass panel, a multiple pane may be composed of three or more glass panels in total which are stacked and separated by a predetermined space individually. In this case, the multiple pane according to the present disclosure may be contained as a part in a thickness direction of a multiple pane. Therefore, the multiple pane according to the present disclosure may include various mode such as a mode where a multiple pane containing enclosed inert gas between the pair of glass panels is provided on the multiple pane according to the present disclosure, a mode where a multiple pane formed by the method according to the present disclosure or another method is further provided on the multiple pane according to the present disclosure, a mode where a multiple pane in which glass panels are simply stacked at a predetermined interval and a space therebetween still has the atmospheric pressure is provided on the multiple pane according to the present disclosure.

Note that the multiple pane according to the present disclosure is successfully used as a window pane serving as eco-glass which shows a high heat insulating effect and is easy to be handled. Besides, application for household use or business use is expected because the multiple pane provided in a refrigerator or a freezer does not interfere with functions of the refrigerator or the freezer and allows an inner condition to be confirmed.

As described above, the applicant provides an embodiment that the applicant considers as the best mode, and other embodiments using the attached drawings and/or the detailed description. These are provided for the purpose of exemplifying the subject matters of claims for persons skilled in the art by reference to the particular embodiment. Therefore, the components shown in the drawings and described in the detailed description includes not only essential components for solving the problem but also the other components. Hence, by reason of being illustrated in the drawings and/or described in the detailed description, these non-essential components are not to be recognized immediately as being essential. Furthermore, within a range including claims and equivalents to the claims, various modification, substitution, addition, and omission may be performed regarding the aforementioned embodiment.

While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present teachings.

A multiple pane according to the first aspect of the present disclosure includes: a pair of glass panels; and a plurality of spacers interposed between the pair of glass panels to keep a distance between the pair of panels to be constant. Peripheries of the glass panels are hermetically bonded. The multiple pane contains a space to be sealed between the glass panels, and the space is in reduced pressure state. Each of the spacers includes at least one layer of a porous member.

In the multiple pane according to the second aspect of the present disclosure referring to the first aspect, each of the spacers is porous glass.

In the multiple pane according to the third aspect of the present disclosure referring to the first or second aspect, at least one glass panel of the pair of glass panels has a film which allows visible radiation to pass therethrough but reflects infrared radiation.

In the multiple pane according to the fourth aspect of the present disclosure referring to any one of the first to third aspects, the porous member contains hollow silica.

In the multiple pane according to the fifth aspect of the present disclosure referring to any one of the first to third aspects, the porous member contains crystallized glass and filler.

In the multiple pane according to the sixth aspect of the present disclosure referring to any one of the first to third aspects, the porous member contains a metal oxide material with electrical conductivity.

In the multiple pane according to the seventh aspect of the present disclosure referring to any one of the first to third aspects, the porous member has a face in contact with the glass pane, and the face is in an U-shape or a projecting shape.

In the multiple pane according to the eighth aspect of the present disclosure referring to any one of the first to third aspects, each of the plurality of spacers is a porous member and contains two layers. A layer of the two layers is in contact with the glass panel and made of a material having adhesion to glass.

In the multiple pane according to the ninth aspect of the present disclosure referring to any one of the first to third aspects, each of the plurality of spacers is a porous member and contains two layers. A layer out of the two layers is in contact with the glass panel and made of a material having heat-barrier properties.

In the multiple pane according to the tenth aspect of the present disclosure referring to any one of the first to ninth aspects, an interval between spacers on a peripheral region of the glass panel is different from an interval between spacers on a central region of the glass panel.

In the multiple pane according to the eleventh aspect of the present disclosure referring to any one of the first to ninth aspects, a size of the spacers on a peripheral region of the glass panel is different from a size of the spacers on a central region of the glass panel.

A method of preparing a multiple pane according to the twelfth aspect of the present disclosure, includes: arranging a pair of glass panels so as to face each other and be separated from each other at a predetermined distance by a spacer; bonding peripheries of the pair of glass panels to form a space to be sealed between the glass panels; making the space be in a reduced pressure state, in which the spacer is made from a photosensitive paste and includes one or more layer of porous glass.

INDUSTRIAL APPLICABILITY

As described above, a multiple pane according to the present disclosure is highly useful, and can be used in various applications such as a window pane, a window member for looking inside a refrigerator, and the like, as a highly useful multiple pane. 

The invention claimed is:
 1. A multiple pane comprising: a pair of glass panels; a plurality of spacers interposed between the pair of glass panels; and a hermetic bond that hermetically bonds peripheries of the pair of glass panels to each other, the multiple pane comprising a space provided between the pair of glass panels, the space being sealed so as to be in a reduced pressure state, each of the plurality of spacers being a porous member provided on one glass panel of the pair of glass panels, and the porous member containing a plurality of hollow silica particles each of which includes a hollow space therewithin.
 2. The multiple pane according to claim 1, wherein the plurality of spacers comprise a mixture of material to compose the plurality of spacers that contain the plurality of hollow silica particles, and a binder, and each of the plurality of spacers has pores provided by removing the binder, and pores that the plurality of hollow silica particles have therewithin.
 3. The multiple pane according to claim 1, wherein each of the plurality of spacers comprises porous glass.
 4. The multiple pane according to claim 1, wherein each of the plurality of spacers comprises the porous member containing a filler of a heat-resistant ceramic.
 5. The multiple pane according to claim 1, wherein the porous member further contains crystalized glass.
 6. The multiple pane according to claim 1, wherein each of the plurality of spacers comprises the porous member containing a metal oxide material with electrical conductivity.
 7. The multiple pane according to claim 1, wherein each of the plurality of spacers has a porosity ranging from 1% to 20%.
 8. The multiple pane according to claim 1, wherein each of the plurality of spacers comprises the porous member that includes at least two layers, the at least two layers include a layer in contact with one of the pair of glass panels on which the spacers are not provided, and the layer has the highest adhesiveness to glass of the at least two layers.
 9. The multiple pane according to of claim 1, wherein each of the plurality of spacers comprises the porous member that includes at least two layers, the at least two layers include a layer in contact with one of the pair of glass panels on which the spacers are not provided, and the layer has the highest heat-barrier properties of the at least two layers.
 10. The multiple pane according to claim 1, wherein each of the plurality of hollow silica particles has a particle diameter of 10 to 300 nm and a shell thickness of 1 to 15 nm. 